Photo-induced reduction-oxidation chemistry of carbon nanotubes

Abstract

Described herein is a method for the photo-induced reduction/oxidation of carbon nanotubes, and their use in photochemical cells and in electrochemical cells for the generation of hydrogen.

1. A photochemical cell comprising:
 a) an anode; 
 b) a cathode; and 
 c) an electrolyte comprising:
 i) a transition metal complex having an absorption band with a maximum between 300 and 600 nm and an extinction coefficient more than about 10 M −1  cm −1 ; and 
 ii) a population of carbon nanotubes dispersed in an aqueous containing medium. 
 
 
     
     
       2. The photochemical cell according to  claim 1  wherein the transition metal complex is comprised of Ru, Os or Fe. 
     
     
       3. The photochemical cell according to  claim 1  wherein the transition metal complex is comprised of optionally substituted polypyridyl ligands. 
     
     
       4. The photochemical cell according to  claim 1  wherein the population of carbon nanotubes is dispersed by a charged dispersant. 
     
     
       5. The photochemical cell according to  claim 4  wherein the charged dispersant is a polymer. 
     
     
       6. The photochemical cell according to  claim 5  wherein the polymer is selected from the group consisting of nucleic acids, polypeptides, and peptide nucleic acids. 
     
     
       7. The photochemical cell according to  claim 1  wherein the dispersed carbon nanotubes are single walled nanotubes. 
     
     
       8. The photochemical cell according to  claim 1  wherein the aqueous containing medium is selected from the group consisting of a solution, a gel and a film. 
     
     
       9. An apparatus to generate hydrogen, comprising:
 a) an anode; 
 b) a cathode; and 
 c) an electrolyte comprising:
 i) a transition metal complex having an absorption band with a maximum between 300 and 600 nm and an extinction coefficient more than about 10 M −1  cm −1 ; 
 ii) a population of carbon nanotubes dispersed in an aqueous containing medium at acidic pH; and 
 iii) an electron donor. 
 
 
     
     
       10. The apparatus according to  claim 9  wherein the transition metal complex is comprised of Ru, Os or Fe. 
     
     
       11. The apparatus according to  claim 9  wherein the transition metal complex is comprised of optionally substituted polypyridyl ligands. 
     
     
       12. The apparatus according to  claim 9  wherein the electron donor is one or more of hydrazine, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), o-tolidine dihydrochloride, violuric acid, 3-hydroxyanthranilic acid, sodium 3-hydroxy-4-nitrosonaphthalene-2,7-disulfonate (NNS), promazine, squaric acid, H 2 O, H 2 O 2 , H 2 S, I − , ascorbic acid, glutathione, 2-mercaptoethanol, dithiothreitol, sodium dithionite, nicotinamide adenine dinucleotide, or nicotinamide adenine dinucleotide phosphate. 
     
     
       13. The apparatus according to  claim 9  wherein the population of carbon nanotubes is dispersed by a charged dispersant. 
     
     
       14. The apparatus according to  claim 13  wherein the charged dispersant is a polymer. 
     
     
       15. The apparatus according to  claim 14  wherein the polymer is selected from the group consisting of nucleic acids, polypeptides, and peptide nucleic acids. 
     
     
       16. The apparatus according to  claim 9  wherein the dispersed carbon nanotubes are single walled nanotubes. 
     
     
       17. The apparatus according to  claim 9  wherein the aqueous containing medium is selected from the group consisting of a solution, a gel and a film. 
     
     
       18. The apparatus according to  claim 9  wherein the aqueous containing medium is at pH of about 1 to about 6.